Port r11704 to MIPS.

src/mips/regexp-macro-assembler-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 763 matching lines @@
         __ Addu(a1, a1, Operand(a2));
         // a1 is length of string in characters.
 
         ASSERT_EQ(0, num_saved_registers_ % 2);
         // Always an even number of capture registers. This allows us to
         // unroll the loop once to add an operation between a load of a register
         // and the following use of that register.
         for (int i = 0; i < num_saved_registers_; i += 2) {
           __ lw(a2, register_location(i));
           __ lw(a3, register_location(i + 1));
-          if (global()) {
+          if (i == 0 && global_with_zero_length_check()) {
             // Keep capture start in a4 for the zero-length check later.
             __ mov(t7, a2);
           }
           if (mode_ == UC16) {
             __ sra(a2, a2, 1);
             __ Addu(a2, a2, a1);
             __ sra(a3, a3, 1);
             __ Addu(a3, a3, a1);
           } else {
             __ Addu(a2, a1, Operand(a2));
@@ skipping 21 matching lines @@
         __ mov(v0, a0);
         __ Branch(&return_v0, lt, a1, Operand(num_saved_registers_));
 
         __ sw(a1, MemOperand(frame_pointer(), kNumOutputRegisters));
         // Advance the location for output.
         __ Addu(a2, a2, num_saved_registers_ * kPointerSize);
         __ sw(a2, MemOperand(frame_pointer(), kRegisterOutput));
 
         // Prepare a0 to initialize registers with its value in the next run.
         __ lw(a0, MemOperand(frame_pointer(), kInputStartMinusOne));
-        // Special case for zero-length matches.
-        // t7: capture start index
-        // Not a zero-length match, restart.
-        __ Branch(
-            &load_char_start_regexp, ne, current_input_offset(), Operand(t7));
-        // Offset from the end is zero if we already reached the end.
-        __ Branch(&exit_label_, eq, current_input_offset(), Operand(zero_reg));
-        // Advance current position after a zero-length match.
-        __ Addu(current_input_offset(),
-                current_input_offset(),
-                Operand((mode_ == UC16) ? 2 : 1));
+
+        if (global_with_zero_length_check()) {
+          // Special case for zero-length matches.
+          // t7: capture start index
+          // Not a zero-length match, restart.
+          __ Branch(
+              &load_char_start_regexp, ne, current_input_offset(), Operand(t7));
+          // Offset from the end is zero if we already reached the end.
+          __ Branch(&exit_label_, eq, current_input_offset(), Operand(zero_reg));
+          // Advance current position after a zero-length match.
+          __ Addu(current_input_offset(),
+                  current_input_offset(),
+                  Operand((mode_ == UC16) ? 2 : 1));
+        }
+
         __ Branch(&load_char_start_regexp);
       } else {
         __ li(v0, Operand(SUCCESS));
       }
     }
     // Exit and return v0.
     __ bind(&exit_label_);
     if (global()) {
       __ lw(v0, MemOperand(frame_pointer(), kSuccessfulCaptures));
     }
@@ skipping 519 matching lines @@
 }
 
 
 #undef __
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS